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Danila F, Schreiber T, Ermakova M, Hua L, Vlad D, Lo S, Chen Y, Lambret‐Frotte J, Hermanns AS, Athmer B, von Caemmerer S, Yu S, Hibberd JM, Tissier A, Furbank RT, Kelly S, Langdale JA. A single promoter-TALE system for tissue-specific and tuneable expression of multiple genes in rice. Plant Biotechnol J 2022; 20:1786-1806. [PMID: 35639605 PMCID: PMC9398400 DOI: 10.1111/pbi.13864] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 05/06/2022] [Accepted: 05/26/2022] [Indexed: 06/15/2023]
Abstract
In biological discovery and engineering research, there is a need to spatially and/or temporally regulate transgene expression. However, the limited availability of promoter sequences that are uniquely active in specific tissue-types and/or at specific times often precludes co-expression of multiple transgenes in precisely controlled developmental contexts. Here, we developed a system for use in rice that comprises synthetic designer transcription activator-like effectors (dTALEs) and cognate synthetic TALE-activated promoters (STAPs). The system allows multiple transgenes to be expressed from different STAPs, with the spatial and temporal context determined by a single promoter that drives expression of the dTALE. We show that two different systems-dTALE1-STAP1 and dTALE2-STAP2-can activate STAP-driven reporter gene expression in stable transgenic rice lines, with transgene transcript levels dependent on both dTALE and STAP sequence identities. The relative strength of individual STAP sequences is consistent between dTALE1 and dTALE2 systems but differs between cell-types, requiring empirical evaluation in each case. dTALE expression leads to off-target activation of endogenous genes but the number of genes affected is substantially less than the number impacted by the somaclonal variation that occurs during the regeneration of transformed plants. With the potential to design fully orthogonal dTALEs for any genome of interest, the dTALE-STAP system thus provides a powerful approach to fine-tune the expression of multiple transgenes, and to simultaneously introduce different synthetic circuits into distinct developmental contexts.
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Affiliation(s)
- Florence Danila
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Plant Sciences Division, Research School of BiologyAustralian National UniversityCanberraAustralian Capital TerritoryAustralia
| | - Tom Schreiber
- Department of Cell and Metabolic BiologyLeibniz Institute of Plant BiochemistryHalleGermany
| | - Maria Ermakova
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Plant Sciences Division, Research School of BiologyAustralian National UniversityCanberraAustralian Capital TerritoryAustralia
| | - Lei Hua
- Department of Plant SciencesUniversity of CambridgeCambridgeUK
| | - Daniela Vlad
- Department of Plant SciencesUniversity of OxfordOxfordUK
| | - Shuen‐Fang Lo
- Biotechnology CenterNational Chung Hsing UniversityTaichungTaiwan
| | - Yi‐Shih Chen
- Institute of Molecular BiologyAcademia SinicaTaipeiTaiwan
| | | | - Anna S. Hermanns
- Department of Plant SciencesUniversity of OxfordOxfordUK
- Present address:
Plant Breeding and Genetics Section, School of Integrative Plant ScienceCornell UniversityIthacaNew YorkUSA
| | - Benedikt Athmer
- Department of Cell and Metabolic BiologyLeibniz Institute of Plant BiochemistryHalleGermany
| | - Susanne von Caemmerer
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Plant Sciences Division, Research School of BiologyAustralian National UniversityCanberraAustralian Capital TerritoryAustralia
| | - Su‐May Yu
- Biotechnology CenterNational Chung Hsing UniversityTaichungTaiwan
- Institute of Molecular BiologyAcademia SinicaTaipeiTaiwan
| | | | - Alain Tissier
- Department of Cell and Metabolic BiologyLeibniz Institute of Plant BiochemistryHalleGermany
| | - Robert T. Furbank
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Plant Sciences Division, Research School of BiologyAustralian National UniversityCanberraAustralian Capital TerritoryAustralia
| | - Steven Kelly
- Department of Plant SciencesUniversity of OxfordOxfordUK
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Ji J, Yang L, Fang Z, Zhang Y, Zhuang M, Lv H, Wang Y. Plant SWEET Family of Sugar Transporters: Structure, Evolution and Biological Functions. Biomolecules 2022; 12:biom12020205. [PMID: 35204707 PMCID: PMC8961523 DOI: 10.3390/biom12020205] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Revised: 01/17/2022] [Accepted: 01/18/2022] [Indexed: 12/20/2022] Open
Abstract
The SWEET (sugars will eventually be exported transporter) family was identified as a new class of sugar transporters that function as bidirectional uniporters/facilitators and facilitate the diffusion of sugars across cell membranes along a concentration gradient. SWEETs are found widely in plants and play central roles in many biochemical processes, including the phloem loading of sugar for long-distance transport, pollen nutrition, nectar secretion, seed filling, fruit development, plant–pathogen interactions and responses to abiotic stress. This review focuses on advances of the plant SWEETs, including details about their discovery, characteristics of protein structure, evolution and physiological functions. In addition, we discuss the applications of SWEET in plant breeding. This review provides more in-depth and comprehensive information to help elucidate the molecular basis of the function of SWEETs in plants.
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Affiliation(s)
- Jialei Ji
- Correspondence: ; Tel.: +86-10-82108756
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Becker S, Mücke S, Grau J, Boch J. OUP accepted manuscript. Nucleic Acids Res 2022; 50:2387-2400. [PMID: 35150566 PMCID: PMC8887545 DOI: 10.1093/nar/gkac098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 01/28/2022] [Accepted: 02/02/2022] [Indexed: 11/25/2022] Open
Abstract
Transcription activator-like effectors (TALEs) are bacterial proteins with a programmable DNA-binding domain, which turned them into exceptional tools for biotechnology. TALEs contain a central array of consecutive 34 amino acid long repeats to bind DNA in a simple one-repeat-to-one-nucleotide manner. However, a few naturally occurring aberrant repeat variants break this strict binding mechanism, allowing for the recognition of an additional sequence with a −1 nucleotide frameshift. The limits and implications of this extended TALE binding mode are largely unexplored. Here, we analyse the complete diversity of natural and artificially engineered aberrant repeats for their impact on the DNA binding of TALEs. Surprisingly, TALEs with several aberrant repeats can loop out multiple repeats simultaneously without losing DNA-binding capacity. We also characterized members of the only natural TALE class harbouring two aberrant repeats and confirmed that their target is the major virulence factor OsSWEET13 from rice. In an aberrant TALE repeat, the position and nature of the amino acid sequence strongly influence its function. We explored the tolerance of TALE repeats towards alterations further and demonstrate that inserts as large as GFP can be tolerated without disrupting DNA binding. This illustrates the extraordinary DNA-binding capacity of TALEs and opens new uses in biotechnology.
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Affiliation(s)
- Sebastian Becker
- Department of Plant Biotechnology, Institute of Plant Genetics, Leibniz Universität Hannover, 30419 Hannover, Germany
| | - Stefanie Mücke
- Department of Plant Biotechnology, Institute of Plant Genetics, Leibniz Universität Hannover, 30419 Hannover, Germany
| | - Jan Grau
- Institute of Computer Science, Martin Luther University Halle-Wittenberg, 06120 Halle (Saale), Germany
| | - Jens Boch
- To whom correspondence should be addressed. Tel: +49 511 762 4082; Fax: +49 511 762 4088;
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Erkes A, Mücke S, Reschke M, Boch J, Grau J. Epigenetic features improve TALE target prediction. BMC Genomics 2021; 22:914. [PMID: 34965853 PMCID: PMC8717664 DOI: 10.1186/s12864-021-08210-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 11/25/2021] [Indexed: 11/20/2022] Open
Abstract
Background The yield of many crop plants can be substantially reduced by plant-pathogenic Xanthomonas bacteria. The infection strategy of many Xanthomonas strains is based on transcription activator-like effectors (TALEs), which are secreted into the host cells and act as transcriptional activators of plant genes that are beneficial for the bacteria.The modular DNA binding domain of TALEs contains tandem repeats, each comprising two hyper-variable amino acids. These repeat-variable diresidues (RVDs) bind to their target box and determine the specificity of a TALE.All available tools for the prediction of TALE targets within the host plant suffer from many false positives. In this paper we propose a strategy to improve prediction accuracy by considering the epigenetic state of the host plant genome in the region of the target box. Results To this end, we extend our previously published tool PrediTALE by considering two epigenetic features: (i) chromatin accessibility of potentially bound regions and (ii) DNA methylation of cytosines within target boxes. Here, we determine the epigenetic features from publicly available DNase-seq, ATAC-seq, and WGBS data in rice.We benchmark the utility of both epigenetic features separately and in combination, deriving ground-truth from RNA-seq data of infections studies in rice. We find an improvement for each individual epigenetic feature, but especially the combination of both.Having established an advantage in TALE target predicting considering epigenetic features, we use these data for promoterome and genome-wide scans by our new tool EpiTALE, leading to several novel putative virulence targets. Conclusions Our results suggest that it would be worthwhile to collect condition-specific chromatin accessibility data and methylation information when studying putative virulence targets of Xanthomonas TALEs. Supplementary Information The online version contains supplementary material available at (10.1186/s12864-021-08210-z).
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Affiliation(s)
- Annett Erkes
- Institute of Computer Science, Martin Luther University Halle-Wittenberg, Halle, Germany.
| | - Stefanie Mücke
- Institute of Plant Genetics, Leibniz Universität Hannover, Hannover, Germany
| | - Maik Reschke
- Institute of Plant Genetics, Leibniz Universität Hannover, Hannover, Germany
| | - Jens Boch
- Institute of Plant Genetics, Leibniz Universität Hannover, Hannover, Germany
| | - Jan Grau
- Institute of Computer Science, Martin Luther University Halle-Wittenberg, Halle, Germany.
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Gupta PK, Balyan HS, Gautam T. SWEET genes and TAL effectors for disease resistance in plants: Present status and future prospects. Mol Plant Pathol 2021; 22:1014-1026. [PMID: 34076324 PMCID: PMC8295518 DOI: 10.1111/mpp.13075] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 03/13/2021] [Accepted: 04/28/2021] [Indexed: 06/12/2023]
Abstract
SWEET genes encode sugar transporter proteins and often function as susceptibility (S) genes. Consequently, the recessive alleles of these SWEET genes provide resistance. This review summarizes the available literature on the molecular basis of the role of SWEET genes (as S genes) in the host and corresponding transcription activator-like effectors (TALEs) secreted by the pathogen. The review has four major sections, which follow a brief introduction: The first part gives some details about the occurrence and evolution of SWEET genes in approximately 30 plant species; the second part gives some details about systems where (a) SWEET genes with and without TALEs and (b) TALEs without SWEET genes cause different diseases; the third part summarizes the available information about TALEs along with interfering/truncated TALEs secreted by the pathogens; this section also summarizes the available information on effector-binding elements (EBEs) available in the promoters of either the SWEET genes or the Executor R genes; the code that is used for binding of TALEs to EBEs is also described in this section; the fourth part gives some details about the available approaches that are being used or can be used in the future for exploiting SWEET genes for developing disease-resistant cultivars. The review concludes with a section giving conclusions and future possibilities of using SWEET genes for developing disease-resistant cultivars using different approaches, including conventional breeding and genome editing.
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Affiliation(s)
| | | | - Tinku Gautam
- Department of Genetics and Plant BreedingCCS UniversityMeerutIndia
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Zlobin N, Lebedeva M, Monakhova Y, Ustinova V, Taranov V. An ERF121 transcription factor from Brassica oleracea is a target for the conserved TAL-effectors from different Xanthomonas campestris pv. campestris strains. Mol Plant Pathol 2021; 22:618-624. [PMID: 33650275 PMCID: PMC8035633 DOI: 10.1111/mpp.13048] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 01/19/2021] [Accepted: 02/04/2021] [Indexed: 05/19/2023]
Abstract
Transcription activator-like effectors (TALEs), which induce the expression of specific plant genes to promote infection, are the main pathogenic determinants of various Xanthomonas bacteria. However, investigation of TALEs from Xanthomonas campestris pv. campestris, which causes black rot disease of crucifers, received little attention. In this study, we used PCR-based amplification followed by SMRT amplicon sequencing to identify TALE genes in several X. campestris pv. campestris strains. Computational prediction in conjunction with quantitative reverse transcription PCR analysis was used to find their targets in the Brassica oleracea genome. Transcription factor ERF121, from the AP2/ERF family, was identified as target gene for the conserved TALEs from multiple X. campestris pv. campestris strains. Several members of this family from diverse plants were previously identified as targets of TALEs from different Xanthomonas species. We propose that TALE-dependent activation of AP2/ERF transcription factors promotes susceptibility to Xanthomonas through the misregulation of plant defence pathways.
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Affiliation(s)
- Nikolay Zlobin
- Laboratory of Plant Stress ToleranceAll‐Russia Research Institute of Agricultural BiotechnologyMoscowRussia
| | - Marina Lebedeva
- Laboratory of Plant Stress ToleranceAll‐Russia Research Institute of Agricultural BiotechnologyMoscowRussia
| | - Yuliya Monakhova
- Laboratory of Synthesis and Analysis of Bioorganic CompoundsAll‐Russia Research Institute of Agricultural BiotechnologyMoscowRussia
| | - Vera Ustinova
- Pushchino Scientific Center for Biological Research of the Russian Academy of SciencesG.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms of the Russian Academy of SciencesPushchinoRussia
- Syntol LLCMoscowRussia
| | - Vasiliy Taranov
- Laboratory of Plant Stress ToleranceAll‐Russia Research Institute of Agricultural BiotechnologyMoscowRussia
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Zárate-Chaves CA, Osorio-Rodríguez D, Mora RE, Pérez-Quintero ÁL, Dereeper A, Restrepo S, López CE, Szurek B, Bernal A. TAL Effector Repertoires of Strains of Xanthomonas phaseoli pv. manihotis in Commercial Cassava Crops Reveal High Diversity at the Country Scale. Microorganisms 2021; 9:315. [PMID: 33557009 DOI: 10.3390/microorganisms9020315] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 12/17/2020] [Accepted: 12/24/2020] [Indexed: 12/13/2022] Open
Abstract
Transcription activator-like effectors (TALEs) play a significant role for pathogenesis in several xanthomonad pathosystems. Xanthomonas phaseoli pv. manihotis (Xpm), the causal agent of Cassava Bacterial Blight (CBB), uses TALEs to manipulate host metabolism. Information about Xpm TALEs and their target genes in cassava is scarce, but has been growing in the last few years. We aimed to characterize the TALE diversity in Colombian strains of Xpm and to screen for TALE-targeted gene candidates. We selected eighteen Xpm strains based on neutral genetic diversity at a country scale to depict the TALE diversity among isolates from cassava productive regions. RFLP analysis showed that Xpm strains carry TALomes with a bimodal size distribution, and affinity-based clustering of the sequenced TALEs condensed this variability mainly into five clusters. We report on the identification of 13 novel variants of TALEs in Xpm, as well as a functional variant with 22 repeats that activates the susceptibility gene MeSWEET10a, a previously reported target of TAL20Xam668. Transcriptomics and EBE prediction analyses resulted in the selection of several TALE-targeted candidate genes and two potential cases of functional convergence. This study provides new bases for assessing novel potential TALE targets in the Xpm–cassava interaction, which could be important factors that define the fate of the infection.
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Neja SA. Site-Specific DNA Demethylation as a Potential Target for Cancer Epigenetic Therapy. Epigenet Insights 2020; 13:2516865720964808. [PMID: 35036833 PMCID: PMC8756105 DOI: 10.1177/2516865720964808] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2020] [Accepted: 09/13/2020] [Indexed: 12/13/2022] Open
Abstract
Aberrant promoter DNA hypermethylation is a typical characteristic of cancer and it is often seen in malignancies. Recent studies showed that regulatory cis-elements found up-stream of many tumor suppressor gene promoter CpG island (CGI) attract DNA methyltransferases (DNMT) that hypermethylates and silence the genes. As epigenetic alterations are potentially reversible, they make attractive targets for therapeutic intervention. The currently used decitabine (DAC) and azacitidine (AZA) are DNMT inhibitors that follow the passive demethylation pathway. However, they lead to genome-wide demethylation of CpGs in cells, which makes difficult to use it for causal effect analysis and treatment of specific epimutations. Demethylation through specific demethylase enzymes is thus critical for epigenetic resetting of silenced genes and modified chromatins. Yet DNA-binding factors likely play a major role to guide the candidate demethylase enzymes upon its fusion. Before the advent of clustered regulatory interspaced short palindromic repeats (CRISPR), both zinc finger proteins (ZNFs) and transcription activator-like effector protein (TALEs) were used as binding platforms for ten-eleven translocation (TET) enzymes and both systems were able to induce transcription at targeted loci in an in vitro as well as in vivo model. Consequently, the development of site-specific and active demethylation molecular trackers becomes more than hypothetical to makes a big difference in the treatment of cancer in the future. This review is thus to recap the novel albeit distinct studies on the potential use of site-specific demethylation for the development of epigenetic based cancer therapy.
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Xue J, Lu Z, Liu W, Wang S, Lu D, Wang X, He X. The genetic arms race between plant and Xanthomonas: lessons learned from TALE biology. Sci China Life Sci 2020; 64:51-65. [PMID: 32661897 DOI: 10.1007/s11427-020-1699-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 03/29/2020] [Indexed: 10/23/2022]
Abstract
The pathogenic bacterial genus Xanthomonas infects a wide variety of host plants and causes devastating diseases in many crops. Transcription activator-like effectors (TALEs) are important virulence factors secreted by Xanthomonas with the ability to directly bind to the promoters of target genes in plant hosts and activate their expression, which often facilitates the proliferation of pathogens. Understanding how plants cope with TALEs will provide mechanistic insights into crop breeding for Xanthomonas defense. Over the past 30 years, numerous studies have revealed the modes of action of TALEs in plant cells and plant defense strategies to overcome TALE attack. Based on these findings, new technologies were adopted for disease management to optimize crop production. In this article, we will review the most recent advances in the evolutionary arms race between plant resistance and TALEs from Xanthomonas, with a specific focus on TALE applications in the development of novel breeding strategies for durable and broad-spectrum resistance.
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Affiliation(s)
- Jiao Xue
- Rice Research Institute, Guangdong Academy of Agricultural Sciences, Guangdong Provincial Key Laboratory of New Technology in Rice Breeding, Guangzhou, 510640, China
| | - Zhanhua Lu
- Rice Research Institute, Guangdong Academy of Agricultural Sciences, Guangdong Provincial Key Laboratory of New Technology in Rice Breeding, Guangzhou, 510640, China
| | - Wei Liu
- Rice Research Institute, Guangdong Academy of Agricultural Sciences, Guangdong Provincial Key Laboratory of New Technology in Rice Breeding, Guangzhou, 510640, China
| | - Shiguang Wang
- Rice Research Institute, Guangdong Academy of Agricultural Sciences, Guangdong Provincial Key Laboratory of New Technology in Rice Breeding, Guangzhou, 510640, China
| | - Dongbai Lu
- Rice Research Institute, Guangdong Academy of Agricultural Sciences, Guangdong Provincial Key Laboratory of New Technology in Rice Breeding, Guangzhou, 510640, China
| | - Xiaofei Wang
- Rice Research Institute, Guangdong Academy of Agricultural Sciences, Guangdong Provincial Key Laboratory of New Technology in Rice Breeding, Guangzhou, 510640, China
| | - Xiuying He
- Rice Research Institute, Guangdong Academy of Agricultural Sciences, Guangdong Provincial Key Laboratory of New Technology in Rice Breeding, Guangzhou, 510640, China.
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Timilsina S, Potnis N, Newberry EA, Liyanapathiranage P, Iruegas-Bocardo F, White FF, Goss EM, Jones JB. Xanthomonas diversity, virulence and plant-pathogen interactions. Nat Rev Microbiol 2020; 18:415-427. [PMID: 32346148 DOI: 10.1038/s41579-020-0361-8] [Citation(s) in RCA: 132] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/19/2020] [Indexed: 12/19/2022]
Abstract
Xanthomonas spp. encompass a wide range of plant pathogens that use numerous virulence factors for pathogenicity and fitness in plant hosts. In this Review, we examine recent insights into host-pathogen co-evolution, diversity in Xanthomonas populations and host specificity of Xanthomonas spp. that have substantially improved our fundamental understanding of pathogen biology. We emphasize the virulence factors in xanthomonads, such as type III secreted effectors including transcription activator-like effectors, type II secretion systems, diversity resulting in host specificity, evolution of emerging strains, activation of susceptibility genes and strategies of host evasion. We summarize the genomic diversity in several Xanthomonas spp. and implications for disease outbreaks, management strategies and breeding for disease resistance.
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Affiliation(s)
- Sujan Timilsina
- Plant Pathology Department, University of Florida, Gainesville, FL, USA
| | - Neha Potnis
- Entomology and Plant Pathology, Auburn University, Auburn, AL, USA
| | - Eric A Newberry
- Entomology and Plant Pathology, Auburn University, Auburn, AL, USA
| | | | | | - Frank F White
- Plant Pathology Department, University of Florida, Gainesville, FL, USA
| | - Erica M Goss
- Plant Pathology Department, University of Florida, Gainesville, FL, USA. .,Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA.
| | - Jeffrey B Jones
- Plant Pathology Department, University of Florida, Gainesville, FL, USA.
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